Process and compositions for production of moldings

ABSTRACT

The present invention relates to a novel chain extender for use in making moldings. The chain extender broadly comprises the reaction product of an aromatic diamine and a cyclic carboxylic acid anhydride.

BACKGROUND OF THE INVENTION

Aromatic diamines which contain at least one alkyl substituent in theortho position to a first amino group and two alkyl substituents in theortho position to a second group are known in the art and are describedas being useful in the preparation of moldings based on polyurethaneand/or polyurea chemistry. See, for example, U.S. Pat. Nos. 4,218,543,4,269,945, 4,288,564, 4,296,212, 4,298,701, 4,379,105, 4,442,235,4,495,081, 4,595,705, 4,595,742, and 4,607,090, and British Patent No.1,534,258. In fact, one of these types of amines has met withsubstantial commercial use in the production of molded parts via the RIMprocess. Specifically, diethyltoluene diamine (DETDA) is currently beingused on a large commercial scale as a chain extender for the productionof polyurethane and polyurea moldings via the RIM process. Formulationsbased on DETDA allow for fast demold times and high productivity becauseof the high reactivity of DETDA. In fact, the concentration of DETDAwhich can be used is generally limited due to the high reactivity.Typical concentrations are in the range of from about 23 to about 25 percent (based on the weight of all the active hydrogen containingcomponents).

Reaction products of ethylenically unsaturated dicarboxylic acidanhydrides (e.g., maleic anhydride) and aromatic diamines are known.Thus the reaction product of one mole of such an acid with from 2 to 20moles of diamine have been described as being useful in the preparationof epoxy based thermosetting resins (see Japanese Published ApplicationNos. 57016023 and 56166225).

DESCRIPTION OF THE INVENTION

The present invention relates to the use of certain reaction products ofspecific aromatic diamines with cyclic carboxylic acid anhydrides. Ithas been discovered that when the reaction products described herein areat equivalent or even higher levels than those when using the unmodifieddiamine, the gel times of the systems are significantly longer. Thisallows the use of higher amounts of chain extender which results instiffer parts with improved heat sag values. Additionally, the moldedparts have excellent green strength.

More particularly, the present invention is directed to a process forthe production of moldings by reacting an organic polyisocyanate, an1000 to 8000 molecular weight organic active hydrogen containingmaterial which contains at least two active hydrogen groups, and a chainextender in a closed mold, where the chain extender comprises thereaction product of

(a) an aromatic diamine which contains at least one non-reactivesubstituent in the ortho position to a first amino group and at leastone non-reactive substituent in the ortho position to a second aminogroup, and

(b) a cyclic carboxylic acid anhydride, with the molar ratio ofcomponent (a) to component (b) being from 3:1 to 15:1, and preferablyfrom 5:1 to 10:1.

The invention is also directed to an active hydrogen group-containingblend for use in the production of moldings comprising an organic activehydrogen group containing material having a molecular weight of from1000 to 8000, and the above noted diamine/anhydride reaction product.

Starting polyisocyanate components suitable for use in the presentinvention include aliphatic, cycloaliphatic, araliphatic, aromatic andheterocyclic polyisocyanates of the type described, for example, by W.Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136.Specific examples of these compounds are ethylene diisocyanate;1,4-tetramethylene diisocyanate; 1,6-hexamethylene diisocyanate;1,12-dodecane diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,3-and -1,4-diisocyanate and mixtures of these isomers.Additional examples are 1-isocyanato-3,3,5-trimethyl-5-isocyanto-methylcyclohexane (German Auslegeschrift No. 1,202,785, U.S. Pat. No.3,401,190), 2,4- and 2,6-hexahydro-tolylene diisocyanate and mixtures ofthese isomers. Hexahydro-1,3- and/or -1,4-phenylene diisocyanate;perhydro-2,4'- and/or -4,4'-diphenylmethane diisocyanate; 1,3- and1,4-phenylene diisocyanate; 1,4- and 2,6-tolylene diisocyanate andmixtures of these isomers are also suitable in the instant invention.Diphenylmethane-2,4-and/or -4,4'-diisocyanate;naphthylene-1,5-diisocyanate; triphenyl methane-4,4',4"-triisocyanate;polyphenyl polymethylene polyisocyanates of the type obtained bycondensing aniline with formaldehyde, followed by phosgenation anddescribed, for example, in British Patent Nos. 874,430 and 848,671 mayalso be used in the present invention; m- andp-isocyanato-phenylsulfonyl isocyanates according to U.S. Pat. No.3,454,606; perchlorinated aryl polyisocyanates of the type described,for example, in German Auslegeschrift No. 1,157,601 (U.S. Pat. No.3,277,138); polyisocyanates containing carbodiimide groups of the typedescribed in German Patent No. 1,902,007 (U.S. Pat. No. 3,152,162);diisocyanates of the type described in U.S. Pat. No. 3,492,330; andpolyisocyanates containing allophanate groups of the type described, forexample, in British Patent No. 993,890, in Belgian Patent No. 761,626and in published Dutch Patent Application No. 7,102,524 are stillfurther examples of suitable isocyanates. Additionally, polyisocyanatescontaining isocyanurate groups of the type described, for example, inU.S. Pat. No. 3,001,973; in German Patent Nos. 1,022,789; 1,222,067 and1,027,394 and in German Offenlegungsschriften Nos. 1,929,034 and2,004,408; polyisocyanates containing urethane groups of the typedescribed, for example, in Belgian Patent No. 752,261 or in U.S. Pat.No. 3,394,164; polyisocyanates containing acylated urea groups accordingto German Patent No. 1,230,778 and polyisocyanates containing biuretgroups of the type described, for example, in German Patent No.1,101,394 (U.S. Pat. Nos. 3,124,605 and 3,201,372) and in British PatentNo. 889,050 are also soluble.

Polyisocyanates produced by telomerization reactions of the typedescribed, for example, in U.S. Pat. No. 3,654,106; polyisocyanatescontaining ester groups of the type described for example, in BritishPatent Nos. 965,474 and 1,072,956, in U.S. Pat. No. 3,567,763 and inGerman Patent No. 1,231,688; reaction products of the above-mentionedisocyanates with acetals according to German Patent No. 1,072,385 andpolyisocyanates containing polymeric fatty acid residues, according toU.S. Pat. No. 3,455,883 are still further examples of suitableisocyanates.

Aromatic polyisocyanates which are liquid at the processing temperatureare preferably used. The particularly preferred starting polyisocyanatesinclude derivatives of 4,4'-diisocyanato-diphenylmethane which areliquid at room temperature, for example, liquid polyisocyanatescontaining urethane groups of the type obtainable in accordance withGerman Patent No. 1,618,380 (U.S. Pat. No. 3,644,457). These may beproduced, for example, by reacting 1 mole of4,4'-diisocyanato-diphenylmethane with from 0.05 to 0.3 moles of lowmolecular weight diols or triols, preferably polypropylene glycolshaving a molecular weight below 700. Also useful are diisocyanates basedon diphenylmethane diisocyanate containing carbodiimide and/or uretoneimine groups of the type obtainable, for example, in accordance withGerman Patent No. 1,092,007 (U.S. Pat. No. 3,152,162). Mixtures of thesepreferred polyisocyanates can also be used. In general, aliphatic andcycloaliphatic isocyanates are less suitable for the purposes of theinstant invention.

The organic active hydrogen group-containing compounds having molecularweights of from 1000 to 8000 include compounds containing amino groups,thiol groups, carboxyl groups and hydroxyl groups.

The compounds used in the process according to the present invention arepreferably polyhydroxyl polyethers or polyamino polyethers havingmolecular weights of from 1000 to 8000, and most preferably from 3000 to6500. Polyethers are particularly suitable for the process of thepresent invention. Preferred are those having at least 2, and preferably2 or 3 hydroxyl or amino groups. Polyhydroxyl polyethers are known andmay be prepared, e.g., by polymerization of epoxides, such as ethyleneoxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxideor epichlorohydrin, either on their own, e.g., in the presence of BF₃,or by a process of chemical addition of these epoxides, optionally asmixtures or successively, to starting components having reactivehydrogen atoms, such as water, ammonia, alcohols or amines. Examples ofsuitable starting components include ethylene glycol, propyleneglycol-(1,3) or -(1,2), trimethylolpropane,4,4'-dihydroxydiphenylpropane, aniline, ethanolamine or ethylenediamine. Sucrose polyethers which have been described in GermanAuslegeschriften No. 1,176,358 and No. 1,064,938 may also be usedaccording to the present invention. It is in many cases preferred to usepolyethers which contain predominant amounts of primary OH groups (up to90%, by weight, based on all the OH groups present in the polyether).Polyethers modified with vinyl polymers are also suitable. These may beobtained, for example, by the polymerization of styrene andacrylonitrile in the presence of polyethers (U.S. Pat. Nos. 3,383,351;3,304,273; 3,523,083 and 3,110,695; and German Pat. No. 1,152,536).Polybutadienes having OH groups may also be used.

According to the present invention, however, there may also be usedpolyhydroxyl compounds which contain high molecular weight polyadductsor polycondensates in a finely dispersed form or in solution. Suchmodified polyhydroxyl compounds are obtained when polyaddition reactions(e.g. reactions between polyisocyanates and amino functional compounds)or polycondensation reactions (e.g. between formaldehyde and phenolsand/or amines) are directly carried out in situ in the above-mentionedhydroxyl compounds. Processes for the production of this type ofmaterial have been described in German Auslegeschriften Nos. 1,168,075and No. 1,260,142 and in German Offenlegungsschriften Nos. 2,324,134;2,423,984; 2,512,385; 2,513,815; 2,550,796; 2,550,797; 2,550,833 and2,550,862. Such polyhydroxyl compounds may also be obtained according toU.S. Pat. No. 3,869,413 or German Offenlegungsschrift No. 2,550,860 bymixing an aqueous polymer dispersion with a polyhydroxyl compound andthen removing water from the mixture.

According to the present invention, hydroxylcontaining polyesters,polythioethers, polyacetals, polycarbonates or polyester amides of thetype known for the production of both homogeneous and cellularpolyurethanes may also be used instead of or together with polyetherpolyols.

Suitable polyesters containing hydroxyl groups include, reactionproducts of polyhydric, (preferably dihydric alcohols), optionally withthe addition of trihydric alcohols, and polybasic (preferably dibasic)carboxylic acids. Instead of free polycarboxylic acids, thecorresponding polycarboxylic acid anhydrides or correspondingpolycarboxylic acid esters of lower alcohols or mixtures thereof may beused for preparing the polyesters. The polycarboxylic acids may bealiphatic, cycloaliphatic, aromatic and/or heterocyclic and they may besubstituted, e.g., by halogen atoms, and/or may be unsaturated. Thefollowing are mentioned as examples: succinic acid, adipic acid, subericacid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid,trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acidanhydride, hexahydrophthalic acid anhydride, tetrachlorophthalic acidanhydride, endomethylene tetrahydrophthalic acid anhydride, glutaricacid anhydride, maleic acid, maleic acid anhydride, fumaric acid,dimeric and trimeric fatty acids, dimethyl terephthalic acid-bis-glycolesters. The following are examples of suitable polyhydric alcohols:ethylene glycol, propylene glycol-(1,2) and -(1,3), butyleneglycol-(1,4) and -(2,3), hexanediol-(1,6), octanediol-(1,8),neopentylglycol, cyclohexanedimethanol(1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propane-diol, glycerol,trimethylolpropane, hexanetriol-(1,2,6), butanetriol-(1,2,4),trimethylolethane, pentaerythritol, quinitol, mannitol and sorbitol,methyl glycoside, diethylene glycol, triethylene glycol, tetraethyleneglycol, polyethylene glycols, dipropylene glycol, polypropylene glycols,dibutylene glycol and polybutylene glycols. The polyesters may alsocontain a proportion of carboxyl end groups. Polyesters of lactones,such as ξ-caprolactone or hydroxycarboxylic acids such asω-hydroxycaproic acid may also be used.

Particularly to be mentioned among the polythioethers are thecondensation products obtained by reacting thiodiglycol on its ownand/or with other glycols, dicarboxylic acids, formaldehyde,aminocarboxylic acids or amino alcohols. The products obtained arepolythiomixed ethers, polythioether esters or polythioether esteramides, depending on the co-components.

Suitable polyacetals include, for example, the compounds which may beprepared from glycols, such as diethylene glycol, triethylene glycol,4,4'-dioxethoxydiphenyldimethyl methane and hexanediol, andformaldehyde. Suitable polyacetals for the purpose of the presentinvention may also be prepared by the polymerization of cyclic acetals.

The polycarbonates containing hydroxyl groups used may be of the typeknown. Highly useful are those which may be prepared by the reaction ofdiols, such as propanediol-(1,3), butane-(1,4) and/or hexanediol-(1,6),diethylene glycol, triethylene glycol or tetraethylene glycol withdiarylcarbonates, e.g., diphenylcarbonate, or phosgene.

Suitable polyester amides and polyamides include, for example, thepredominantly linear condensates prepared from polybasic saturated andunsaturated carboxylic acids or the anhydrides thereof and polyvalentsaturated or unsaturated amino alcohols, diamines, polyamines andmixtures thereof.

Representatives of the hydroxyl functional compounds which may be usedaccording to the present invention are generally known and have beendescribed, for example, in High Polymers, Vol. XVI, "Polyurethanes,Chemistry and Technology" by Saunders-Frisch, Interscience Publishers,New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and VolumeII, 1964, pages 5-6 and 198-199 and in Kunststoff-Handbuch, Volume VII,Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich, 1966, on pages 45 to 71.

Also preferred are polyethers containing primary and/or secondary(preferably primary) aromatically or aliphatically (preferablyaliphatically) bound amino groups.

Compounds containing amino end groups may also be attached to thepolyether chain by urethane or ester groups. These "amino polyethers"may be prepared by known methods. One such method is the amination ofpolyhydroxyl polyethers (e.g., polypropylene glycol ethers) by areaction with ammonia in the presence of Raney nickel and hydrogen(Belgian Patent No. 634,741). U.S. Pat. No. 3,654,370 discloses thepreparation of polyoxyalkylene polyamines by reaction of thecorresponding polyol with ammonia and hydrogen in the presence of anickel, copper or chromium catalyst. The preparation of polyetherscontaining amino end groups by the hydrogenation of cyanoethylatedpolyoxypropylene ethers is described in German Patent No. 1,193,671.Other methods for the preparation of polyoxyalkylene (polyether) aminesare described in U.S. Pat. Nos. 3,155,728 and 3,236,895 and FrenchPatent No. 1,551,605. French Patent No. 1,466,708 discloses thepreparation of polyethers containing secondary amino end groups.

Relatively high molecular weight polyhydroxypolyethers suitable for theprocess of the present invention may be converted into the correspondinganthranilic acid esters by reaction with isatoic acid anhydride. GermanOffenlegungsschriften Nos. 2,019,432 and 2,619,840 and U.S. Pat. Nos.3,808,250; 3,975,428 and 4,016,143 disclose methods for makingpolyethers containing aromatic amino end groups.

Relatively high molecular weight compounds containing amino end groupsmay be obtained according to German Offenlegungsschrift No. 2,546,536 orU.S. Pat. No. 3,865,791 by reacting isocyanate prepolymers based onpolyhydroxy polyethers with hydroxyl-containing enamines, aldimines orketimines and hydrolyzing the reaction product.

The aminopolyethers which have been obtained by the hydrolysis ofcompounds containing isocyanate end groups are preferred startingmaterials (German Offenlegungsschrift No. 2,948,419). Polyetherspreferably containing two or three hydroxyl groups are reacted (in theprocess disclosed in German Offenlegungsschrift No. 2,948,419) withpolyisocyanates to form isocyanate prepolymers and the isocyanate groupis then converted in a second step into an amino group by hydrolysis.

The "aminopolyethers" used in the present invention are in many casesmixtures of the compounds described above. These mixtures generallyshould contain (on a statistical average) two to three isocyanatereactive end groups.

In the process of the present invention, the "aminopolyethers" may alsobe used as mixtures with polyhydroxyl polyethers which are free fromamino groups.

In the process according to the present invention, it is preferred touse classical polyether polyols of polyurethane chemistry or of theabove noted polyether polyamines having molecular weights of from 1000to 8000, preferably from 3000 to 6500, and containing two or threehydroxyl or amino groups. Mixtures of polyethers, of course, may also beused.

The chain extender of the present invention comprises the reactionproduct of specific diamines with dicarboxylic acid anhydrides. Thediamines useful herein are those aromatic diamines which contain atleast one non-reactive substituent in the ortho position to a firstamino group, and at least one non-reactive substituent in the orthoposition to a second amino group. By "non-reactive substituents" ismeant a substituent that does not react with the anhydride and whichdoes not react with either isocyanate groups or active hydrogens. It ispreferred that such substituents be alkyl groups, preferably containing1 to 4 carbon atoms. Specific alkyl substituents include methyl, ethyl,n-propyl, isopropyl, t-butyl, and/or methylthio. Specific amines usefulherein include 1-methyl-3,5-diethyl-2,4- and/or -2,6-diaminobenzene,1,3,5-triethyl-2,6-diaminobenzene,3,5,3',5'-tetraethyl-4,4'-diaminodiphenylmethane tertiary butyl toluenediamine and the like. Useful diamines of this type are described in moredetail in U.S. Pat. Nos. 4,218,543, 4,269,945, 4,288,564, 4,296,212,4,298,701, 4,379,105, 4,442,235, 4,495,081, 4,595,705, 4,595,742, and4,607,090, and British Patent No. 1,534,258, the disclosures of whichare herein incorporated by reference. Useful cyclic carboxylic acidanhydrides useful herein include substantially any dicarboxylic acidanhydride. Specific anhydrides include succinic anhydride, glutaricanhydride, phthalic anhydride, maleic anhydride, hexahydrophthalicanhydride, tetrachloro- or tetrabromo phthalic anhydride, 1,8-naphthalicanhydride, tetrahydrophthalic anhydride, chlorendic anhydride, itaconicanhydride, and the like. It is particularly preferred to use maleicanhydride or phthalic anhydride since the resultant product isindefinitely stable in conventional polyethers used to make moldedparts.

The production of the chain extender is relatively simple. The amine andanhydride are generally mixed together, typically at reactiontemperatures of from 150° C. to 220° C., and held at that temperatureuntil the acid number is at or near zero, with the water of reactionbeing distilled off. Where unsaturated anhydrides are used, it may bedesirable to add a free radical inhibitor to prevent polymerization ofthe double bonds. Hydroquinone is a preferred free radical inhibitor.

The amount of chain extender used can be varied over a wide range.Typically it is used in an amount of from 5 to 50% by weight based onthe combined weight of the organic active hydrogen containing materialand the chain extender. It is preferred that the amount used range from10 to 35% by weight, and most preferably from 15 to 30% by weight.

Catalyst is essential to the present invention in the case wherein onlya hydroxyl functional compound or wherein a hydroxyl group containingco-chain extender is used. In these cases, it is not possible withoutcatalyst to obtain a molding which sets rapidly in the mold and hastechnologically interesting mechanical properties, are preferablyselected from the group of organic metal compounds known for use inpolyurethane chemistry. According to the present invention, it ispreferred to use organic tin compounds such as tin(II)salts ofcarboxylic acids, (such as tin(II)-acetate, tin(II)octoate, tin(II)ethylhexoate or tin(II)-laurate), and the dialkyl tin salts of carboxylicacids (such as dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tinmaleate or dioctyl tin diacetate) either alone or most preferably as acomplex with amidines, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidineor 2-methyl-3-cyclohexyl-3,4,5,6-tetrahydropyrimidine, aminopyridines,aminopyrimidines, hydrazino pyridines or hydrazino pyrimidines.Synergistically acting catalysts combinations of this type are known andhave been described, for example, in German Offenlegungsschriften Nos.2,434,185; 2,601,082 and 2,603,834.

Other catalysts which may be used include: known tertiary amines, suchas triethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine,N-cocomorpholine, N,N,N',N'-tetramethyl-ethylenediamine,1,4-diazabicyclo-(2,2,2)-octane,N-methyl-N'-dimethylaminoethylpiperazine, N,N-dimethylbenzylamine,bis-(N,N-diethylaminoethyl)-adipate, N,N-diethylbenzylamine,pentamethyl-diethylene-triamine, N,N'-diamethylcyclohexylamine,N,N,N',N'-tetramethyl-1,3-butanediamine,N,N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole and2-methylimidazole. A preferred catalyst of this type is1,4-diaza-bicyclo-(2,2,2)-octane.

Tertiary amines having isocyanate-reactive hydrogen atoms include, e.g.,triethanolamine, triisopropanolamine, N-methyl-diethanolamine,N-ethyldiethanolamine, and N,N-dimethyl-ethanolamine may also be used.Reaction products of these compounds with alkylene oxides, such aspropylene oxide and/or ethylene oxide are also suitable.

Silaamines having carbon-silicone bonds as described, e.g., in GermanPatent No. 1,229,290 may also be used as catalysts. Examples include2,2,4-trimethyl-2-sila-morpholine or1,3-diethylaminomethyl-tetramethyl-disiloxane.

Basic nitrogen compounds, such as tetralkylammonium hydroxides, alkalimetal hydroxides, such as sodium hydroxide, alkali metal phenolates,such as sodium phenolate, and alkali metal alcoholates, such as sodiummethylate, may also be used as catalysts. Hexahydrotriazines are alsosuitable catalysts.

The above-mentioned catalysts may be used alone, (e.g., most preferably1,4-diaza-bicyclo-(2,2,2)-octane) or in combination with organic metalcompounds, and in particular the organic tin compounds noted above.

Other representatives of catalysts which may be used according to thepresent invention and details concerning the action of the catalysts maybe found, e.g., in Kunststoff-Handbuch, Volume VII, published by Viewegand Hochtlen, Carl-Hanser-Verlag, Munich, 1966, pages 96 to 102.

When used, the catalysts to be used according to the present inventionshould accelerate the polyaddition reaction to such an extent that oncethe starting components have been mixed the reactive mixture has a flowtime (e.g., the capability to flow and hence the time during which themixture may still be delivered) of less than 5, 10 or 15 seconds, anddemolding times of less than 30 seconds. In general, these can beattained by using from 0.001 to 10 percent by weight of catalyst basedon the total weight of component (b).

As noted herein, in some cases it is desirable to utilize a lowmolecular weight hydroxyl functional organic compound (or co-chainextender) having from 2 to 4 hydroxyl groups.

Compounds containing at least two hydroxyl groups and having molecularweights of from 62 to 600 may be used in the present invention aschain-extenders or cross-linkers. The co-chain extenders andcross-linking agents generally contain from 2 to 4 isocyanate-reactivehydrogen atoms. Mixtures of different compounds containing at least twohydroxyl groups and having a molecular weight of from 62 to 600 may alsobe used.

Examples of such low molecular weight compounds are ethylene glycol,1,2- and 1,3-propylene glycol, 1,4-and 2,3-butylene glycol, 1,5-pentanediol, 1,6-hexane diol, 1,8-octane diol, neopentyl glycol,1,4-bis-hydroxy methyl cyclohexane, 2-methyl-1,3-propane diol,dibromobutene diol (U.S. Pat. No. 3,723,392), glycerol, trimethylolpropane, 1,2,6-hexane triol, trimethylol ethane, pentaerythritol,quinitol, mannitol, sorbitol, castor oil, diethylene glycol, triethyleneglycol, tetraethylene glycol, higher polyethylene glycols having amolecular weight of up to 600, dipropylene glycol, higher polypropyleneglycols having a molecular weight of up to 600, dibutylene glycol,higher polybutylene glycols having a molecular weight of up to 600,4,4'-dihydroxydiphenyl propane, dihydroxy methyl hydroquinone, and thelike.

Other low molecular weight polyols having a molecular weight of up to600 which may be used in accordance with the present invention are esterdiols, diol urethanes and diol ureas. Suitable ester diols correspond tothe general formula

    HO--(CH.sub.2).sub.x --CO--O--(CH.sub.2).sub.y --OH

    and

    HO--(CH.sub.2).sub.x --O--CO--R--CO--R--CO--O--(CH.sub.2).sub.x --OH

wherein

R represents an alkylene radical containing from 1 to 10, (preferablyfrom 2 to 6) carbon atoms or a cycloalkylene or arylene radicalcontaining from 6 to 10 carbon atoms;

x represents 2 to 6, and

y represents 3 to 5.

Examples of compounds corresponding to these formulae areδ-hydroxybutyl-ξ-hydroxycaproic acid ester,-hydroxy-hexyl-γ-hydroxybutyric acid ester, adipicacid-bis-(β-hydroxyethyl)-ester and terephthalicacid-bis-(β-hydroxy-ethyl)-ester.

Diol urethanes which may be used in the present invention correspond tothe general formula:

    HO--(CH.sub.2).sub.x --O--CO--NH--R'--N--H--CO--O--(CH.sub.2)--OH

wherein

R' represents an alkylene radical containing from 2 to 15 (preferablyfrom 2 to 6) carbon atoms or a cycloalkylene or arylene radicalcontaining from 6 to 15 carbon atoms, and

x represents a number of from 2 to 6.

Examples of such diol urethanes are 1,6-hexamethylene-bis-(hydroxyethylurethane) and 4,4'-diphenylmethane-bis-(hydroxybutyl urethane). Diolureas suitable to the present invention correspond to the generalformula ##STR1## wherein R" represents an alkylene radical containingfrom 2 to 15 (preferably from 2 to 9) carbon atoms or a cycloalkylene orarylene radical containing from 6 to 15 carbon atoms,

R" represents hydrogen or a methyl group, and

x represents the number 2 or 3.

Examples of such diol ureas are 4,4'-diphenylmethane-bis-(β-hydroxyethyl urea) and the compound ##STR2##

For certain purposes, it may be advantageous to use polyols containingsulfonate and/or phosphonate groups (German Offenlegungsschrift No.2,719,372), such as the adduct of bisulfite with 1,4-butene diol or thealkoxylation product thereof.

In some instances, it may be desired to add additional quantities ofamino chain extender. In such cases, any of the aromatic diaminespreviously described can be used.

The process according to the present invention is preferably used forproducing compact moldings although blowing agents may be used. Theblowing agents used may be water and/or readily volatile organicsubstances and/or dissolved inert gases. Suitable organic blowing agentsinclude, e.g., acetone; ethyl acetate; methanol; ethanol; halogensubstituted alkanes, such as methylene chloride, chloroform, ethylidenechloride, vinylidene chloride, monofluorotrichloromethane,chlorodifluoromethane or dichlorodifluoromethane, butane; hexane;heptane; diethyl ether; and the like. Suitable inert gases includenitrogen, air, carbon dioxide, and the like.

The effect of a blowing agent may also be obtained by adding compoundswhich decompose at temperatures above room temperature to liberate gas,for example, nitrogen. Examples include azo compounds, such asazoisobutyric acid nitrile. Other examples of blowing agents and detailsconcerning the use of blowing agents may be found inKunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen,Carl-Hanser-Verlag, Munich, 1966, pages 108 to 109, 453 to 455 and 507to 510.

Surface-active additives (emulsifiers and foam stabilizers) may also beused according to the present invention. Suitable emulsifiers includethe sodium salts of ricinoleic sulphonates or of fatty acids, or saltsof fatty acids with amines, such as oleic acid diethylamine or stearicacid diethanolamine. Alkali metal or ammonium salts of sulphonic acids,such as dodecylbenzene sulphonic acid or dinaphthylmethane disulphonicacid, or of fatty acids, such as ricinoleic acid, or of polymeric fattyacids may also be used as surface active additives.

The most useful foam stabilizers are primarily water-soluble polyethersiloxanes. These compounds generally have a polydimethylsiloxane groupattached to a copolymer of ethylene oxide and propylene oxide. Foamstabilizers of this type are known and have been described, for example,in U.S. Pat. No. 2,764,565.

Known cell regulators, such as paraffins or fatty alcohols ordimethylpolysiloxanes, pigments, dyes, known flame retarding agents,such as bis-chloroethylphosphate or ammonium phosphate andpolyphosphate, stabilizers against aging and weathering, plasticizers,fungistatic and bacteriostatic substances and fillers, such as bariumsulphate, kieselguhr, carbon black or whiting, and preferably glassreinforcements in the form of flakes and/or fibers may also be usedaccording to the present invention.

Other examples of surface active additives, foam stabilizers, cellregulators, stabilizers, flame retarding substances, plasticizers, dyes,fillers and fungistatic and bacteriostatic substances which may be usedaccording to the present invention and details concerning the use andaction of these additives are known and may be found inKunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen,Carl-Hanser-Verlag, Munich, 1966, pages 103 to 113.

The quantity of polyisocyanate (component (a)) used in the processaccording to the present invention is preferably calculated so that themixture has an isocyanate index of from 70 to 130, in particular from 90to 110. By "isocyanate index" is meant the quotient of the number ofisocyanate groups and the number of groups which are reactive withisocyanates multiplied by 100.

The reaction mixture is processed via the one-shot process. As is knownin the art in the "one-shot" system, the reactive components are mixedsimultaneously as opposed to the prepolymer process, wherein some of thecomponents are prereacted. Thus, the components non-reactive with eachother may first be blended and thereafter processed in a "one-shot"technique.

The known reaction injection molding technique (RIM process) may be usedfor carrying out the process according to the present invention. Thequantity of reaction mixture (which is optionally foamable) introducedinto the mold is chosen so that the molded article generally has adensity of from 0.8 to 1.2 g/cc, preferably from 0.9 to 1.1 g/cc.

A starting temperature of from 10° C. to 50° C., preferably from 20° C.to 30° C. is chosen for the mixture introduced into the mold. Thetemperature of the mold itself is generally from 40° C. to 100° C. andpreferably from 50° C. to 70° C.

Known mold-release agents of the type described, for example, in GermanOffenlegungsschriften Nos. 1,953,637 and 2,121,670, may also be used inthe instant process.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

EXAMPLES EXAMPLE 1

A 12 liter 3 neck flask was charged with 8500 parts of DETDA (an 80/20mixture of 3,5-diethyl-2,4- and 3,5-diethyl-2,6-diaminotoluene) withstirring and a nitrogen purge. The amine was heated to 100° C. 14.1parts of hydroquinone were then added followed by addition of 680 partsof maleic anhydride. After the addition of the anhydride, thetemperature was raised to 160° C., and maintained at that temperatureuntil the acid number of 1.0 was reached. During the reaction, 102 partsof water were distilled off. Thereafter, the mixture was cooled to 100°C. and held at that temperature for 1 hour. The product was then allowedto cool to room temperature.

EXAMPLE 2

A 12 liter 3 neck flask was charged with 6466.8 parts of DETDA withstirring and a nitrogen purge. The amine was heated to 85° C. and 528parts of succinic anhydride were slowly added thereto. When the additionwas complete, the temperature was raised to 200° C. The temperature wasmaintained at 200° C. until the acid number had dropped to 1.0. Duringthe reaction, 66 parts of water were distilled off. The mixture was thenallowed to cool to room temperature.

EXAMPLE 3

A one liter 3 neck flask was charged with 10,000 parts of DETDA withstirring and a nitrogen purge. The amine was heated to 100° C. 1208parts of phthalic anhydride were then added. After the addition of theanhydride, the temperature was raised to 160° C. and maintained at thattemperature until the acid number had dropped to 0.01. During thereaction, 122 parts of water were distilled off. The product was thenallowed to cool to room temperature.

EXAMPLES 4 THROUGH 11

RIM plaques were prepared using a laboratory piston metering unit andclamping unit. The metering unit was a two component instrument having amaximum metering capacity of 0.6 liters. A rectangular mold, 300 mm×200mm×3 mm was used to mold samples under the following conditions:

    ______________________________________                                        Component A (isocyanate) Temp.                                                                        40° C.                                         Component B Temp.       40° C.                                         Isocyanate index        105                                                   Mold Temp.              65° C.                                         Mix Pressure            2940 psi                                              Demold time             35 seconds                                            ______________________________________                                    

The formulations used and the results obtained were as set forth inTable 1. Example 4 was a comparative example. The samples were testedfor density (ASTM D-792), flex modulus (ASTM D-638), tensile strengthand elongation (ASTM D-638), heat sag (ASTM D-3769), and notched Izod(ASTM D-256). The raw materials used were:

POLYOL: a glycerin initiated propylene oxide/ethylene oxide (weightratio of propylene oxide to ethylene oxide is about 4.7:1) polyetherhaving a hydroxyl number of 28 and a molecular weight of about 6000, andcontaining primary hydroxyl groups

DETDA

T-12: dibutyl tin dilaurate

33 LV: Dabco 33 LV, a triethylenediamine available from Air Products

ISO: Mondur PF, a modified isocyanate available from Mobay Corporation,prepared by reacting 4,4'-diphenylmethanediisocyanate with tripropyleneglycol to give a liquid product having an NCO content of about 23% byweight.

                                      TABLE 1                                     __________________________________________________________________________    EXAMPLE     4    5    6    7    8    9    10   11                             __________________________________________________________________________    B-SIDE:                                                                       POLYOL, pbw 80   78.7 77   75.1 73.6 75.1 74.6 73.5                           DETDA, pbw  20   --   --   --   --   --   --   --                             Product of Ex. 1, pbw                                                                     --   21.3 23   24.9 26.4 --   --   --                             Product of Ex. 2, pbw                                                                     --   --   --   --   --   24.9 --   --                             Product of Ex. 3, pbw                                                                     --   --   --   --   --   --   25.4 26.5                           T-12, pbw   0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1                            33 LV, pbw  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1                            A-SIDE:                                                                       ISO, pbw    51.5 48.2 51.3 54.8 57.5 54.8 53.9 55.8                           RESULTS:                                                                      DENSITY, pcf                                                                              68.9 69.1 69.4 69.4 69.8 69.5 69.0 69.4                           FLEX MOD, psi × 10.sup.3                                                            50.7 47.2 57.0 64.0 71.8 57.7 53.7 62.7                           TENS, STR., psi                                                                           4775 4390 4250 4333 4585 4204 4770 4860                           ELONGATION, %                                                                             310  290  240  260  246  330  355  340                            Heat Sag:                                                                     (4", 325° F.), mm                                                                  37.5 36   25.5 27.5 19   29   42.5 34.5                           (6", 250° F.), mm                                                                  27   30   11   19   23.5 15   24.5 30                             Notched Izod,                                                                             11.4 9.6  11.5 10.2 10.5 9.1  10.7 13.0                           ft.-lb/in.                                                                    __________________________________________________________________________

In addition, the formulations of Examples 4, 6 8, 10 and 11 were testedfor gel times. 100 parts by weight of each formulation were introducedinto an open can. Rotational viscosities were then obtained from thereacting mixtures, using a commercially available Servodyne device. Thedata are displayed as viscosity versus time profiles, with the pointwhere the isocyanate is poured into the B-side being zero on the timescale. The time is then measured from this point to where the viscosityvs. time curve becomes vertical. This point is recorded as the gel time.The results obtained were as follows:

    ______________________________________                                        FORMULATION    GEL TIME, seconds                                              ______________________________________                                        4              3.32                                                           6              3.44                                                           8              3.70                                                           10             3.98                                                           11             3.98                                                           ______________________________________                                    

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

What is claimed is:
 1. A process for the production of moldingscomprising reacting an organic polyisocyanate, an organic activehydrogen containing material having a molecular weight of from 1000 to8000 and containing at least two active hydrogen groups, and a chainextender in a closed mold, said chain extender comprising the reactionproduct of(a) an aromatic diamine which contains at least onenon-reactive substituent in the ortho position to a first amino groupand at least one non-reactive substituent in the ortho position to asecond amino group, and (b) a cyclic carboxylic acid anhydride at amolar ratio of component (a) to component (b) of from 3:1 to 15:1. 2.The process of claim 1, wherein said ratio is from 5:1 to 10:1.
 3. Theprocess of claim 1, wherein said non-reactive substituents are C₁ to C₄alkyl groups.
 4. The process of claim 1, wherein said chain extender isused in an amount of from about 5 to about 50% by weight, based on thecombined weight of said active hydrogen containing material and saidchain extender.